The present invention generally relates to an automobile body structure and, more particularly, to an automobile rear body structure, i.e., the structure at the rear of the automobile body structure.
In an automobile body structure wherein the bottom of the rear luggage compartment is delimited by the rear end portion of a rear floor panel which has been stepped down from the remainder of the rear floor panel, longitudinal frames extending in laterally spaced relation to each other in a direction lengthwise of the automobile body structure are arranged beneath the opposite side portions of the rear floor panel and, therefore, the space available for the rear luggage compartment is limited between these longitudinal frames and the space between each of the longitudinal frames and the adjacent rear side panel can not be utilized. In view of this, attempts have been made to utilize the longitudinal frames which are bent so as to follow the contour of the rear floor panel having the downwardly stepped rear end portion, but these attempts were not successful because no sufficient clearance between the ground surface to the longitudinal frames is available.
In order to maximize the available space for the rear luggage compartment without reducing the ground-to-frame clearance, the Japanese Laid-open Utility Model Publication No. 56-4979, published in 1981, discloses such a structure as shown in FIGS. 1 to 3 of the accompanying drawings, reference to which will now be made for the purpose of the discussion of the prior art to which the present invention pertains. However, it is to be noted that, in FIGS. 1 to 3, the automobile rear body structure is shown partially, i.e., only one of the halves of the rear body structure adjacent one of the opposite sides of the automobile body structure as a whole is shown, for the sake of simplicity.
Referring now to FIGS. 1 to 3, for each side of the automobile rear body structure, the longitudinal frame e employed in the prior art structure comprises a frame member c having one end mounted on a highland area of the rear floor panel a and extending rearwardly therefrom towards the rear luggage compartment b, and a frame member d having one end positioned on one side of the highland area of the rear floor panel a opposite to the frame member c and extending frontwardly therefrom, said one end of the frame member c and said one end of the frame member d being connected together in overlapping relation with a kick-up portion of the rear floor panel a intervening therebetween. In this prior art structure, since the longitudinal frame 3 is divided into the two frame members which are positioned so as to confront the interior and exterior of the body structure, respectively, and are connected together through the kick-up portion of the rear floor panel, the longitudinal frame e as a whole does not represent a linear configuration and, accordingly, the prior art rear body structure lacks a sufficient rigidity. By way of example, in the event of a rear-end collision, an impact resulting from the collision acts on the connection between the frame members forming the longitudinal frame 3 so as to axially displace the frame members in a direction close to each other and, in the worst it may happen, the frame members connected together to provide the longitudinal frame 3 would be separated. In addition, the connection between the frame members is complicated and, therefore, the internal reinforcement of the rear body structure to increase the physical strength and the rigidity is not easy with no difficulty.